Technical Field
The present invention relates to an apparatus and a system for detecting vibration energy generated in an inspection object.
Related Art
Nowadays, daily-available environmental energy independent of fossil fuel attracts attention from the viewpoint of energy saving. Electric energy generated by sunlight or wind power is well known as the environmental energy, and daily-available vibration energy can also be cited as the environmental energy having the same energy density as the electric energy generated by the sunlight or wind power. A vibration power generator that generates the power using the vibration energy has been developed, and an electret that can semipermanently retain a charge is widely used in the vibration power generator (for example, see Patent Document 1). In the technology of the vibration power generator in which the electret is used, a movement direction of a movable board that moves reciprocally for the power generation is set to at least two directions different from each other. Therefore, an external vibration is efficiently collected into the vibration power generator to be able to power the generation.
Patent Document 2 discloses an example of a usage form of the vibration power generator. Patent Document 2 discloses a technology concerning the vibration power generator provided in a wrist watch. In the technology, power consumption mode of the wrist watch is switched according to whether the vibration power generator generates the power by the vibration.
On the other hand, the vibration power generator is installed in an inspection object to act as a vibration sensor that directly converts a displacement of the vibration generated in the inspection object into an electric signal. The vibration displacement can be obtained by performing electric processing (double integral) of acceleration detected by an acceleration sensor. However, the vibration detected with the vibration power generator is a useful technique because the power is required for the electric processing. Patent Document 3 discloses a technology of producing vibration information or acceleration information by counting the number of vibrations of an AC voltage generated from the vibration power generator with a counter circuit.